# Paralomis

Paralomis is a widely distributed, highly speciose, and morphologically diverse genus of king crabs in the subfamily Lithodinae.

## Etymology

Paralomis means that it is related to Lomis, and para for the first name mean 'being similar' to Lomis.

## Description

Like all king crabs, Paralomis has evolved a crab-like appearance through a process called carcinisation. Paralomis has either a pentagonal or pyriform carapace. At the very front, its rostrum consists of one short, conical spine projecting forward in the middle and one or more pairs of spines angled upward around the base. Like all king crabs, the gastric region, directly behind the rostrum, is elevated above the others. Like Lithodes and Neolithodes, the cardiac region – directly behind the gastric region, separated by a deep groove – is triangular. Its three pairs of walking legs – morphologically similar, with the middle pair typically being the longest – are not covered at their bases by the carapace. In adults, the undersides of the dactyli feature horn-like spines. The abdomen is more calcified than in other king crab genera: the second segment is undivided, the third segment has fused submedian and marginal (outer) plates, and segments three, four, and five are all entirely calcified.

## Distribution

Paralomis is present in four of Earth's five oceans – namely the Atlantic, Pacific, Indian, and Southern – as well as all seven continents. They are found from the very shallow intertidal zone to the deep, perpetually dark abyssal zone. The deepest known species of Paralomis is P. bouvieri, which has been discovered living at 4,152 m (13,622 ft).

## Taxonomy

Paralomis was described in 1856 by zoologist Adam White and named for its similarity to the genus Lomis. In 1895, marine biologist James Everard Benedict incorrectly placed Paralomis granulosa, the genus' type species, under the genus Lithodes. Benedict therefore dissolved the genus and created two now-defunct ones – Leptolithodes and Pristopus – for other members of Paralomis. Paralomis is closely related to Echidnocerus, and the monospecific genus Glyptolithodes – nested cladistically inside Paralomis – may simply be a species of Paralomis.
Paralomis contains over 70 species – more than any other king crab genus – and is the most morphologically diverse genus in the subfamily Lithodinae. It contains one fossil species, Paralomis debodeorum, which lived in New Zealand in the Middle–Late Miocene. Paralomis is distinguished from other king crabs by its abdominal segments: the second is undivided, and the third, fourth, and fifth are entirely calcified. Current scientific consensus is that Paralomis is monophyletic, although within this group, carcinologist Shane T. Ahyong in 2010 identified several informal subgroups of Paralomis. Paralomis' relationship to other king crabs can be seen in the following cladogram:
Lithodidae cladogram :
Lithodidae
Paralithodes brevipes
Paralomis/Glyptolithodes
Glyptolithodes cristatipes
Paralomis zealandica
Paralomis granulosa
Paralomis dofleini
Paralomis pacifica
Paralomis birsteini
Paralomis cristata
Paralomis formosa
Paralomis multispina
Paralomis hirtella
Paralomis spinosissima
Paralomis erinacea
Paralomis africana
Paralomis cristulata
Paralomis anamerae
Paralomis aculeata
Paralomis elongata
Echidnocerus
Echidnocerus cibarius
Echidnocerus foraminatus
Neolithodes
Neolithodes diomedeae
Neolithodes brodiei
Neolithodes grimaldii
Neolithodes duhameli
Neolithodes asperrimus
Lithodes
Lithodes nintokuae
Lithodes turkayi
Lithodes longispina
Lithodes murrayi
Lithodes aequispinus
Lithodes couesi
Lithodes turritus
Lithodes paulayi
Lithodes ferox
Lithodes maja
Lithodes santolla
Lithodes confundens
Paralithodes platypus
Paralithodes camtschaticus
Phyllolithodes/Rhinolithodes
Phyllolithodes papillosus
Rhinolithodes wosnessenskii
Acantholithodes hispidus
Placetron wosnessenskii
Cryptolithodes
Cryptolithodes sitchensis
Cryptolithodes typicus
Hapalogaster
Hapalogaster mertensii
Hapalogaster grebnitzkii
Hapalogaster dentata
Oedignathus inermis :

## Species

Paralomis contains the following species:
| Scientific name | Common name | Distribution |
| Paralomis aculeata Henderson, 1888 | | Southwest Indian Ridge |
| Paralomis africana Macpherson, 1982 | | Namibia |
| Paralomis alcockiana Hall & Thatje, 2009 | | |
| Paralomis alis Ahyong, 2020 | | |
| Paralomis anamerae Macpherson, 1988 | | Argentina, Crozet Island, South Georgia Island |
| Paralomis arae Macpherson, 2001 | | |
| Paralomis arethusa Macpherson, 1994 | | |
| Paralomis aspera Faxon, 1893 | | |
| Paralomis birsteini Macpherson, 1988 | | Southern Ocean near Scott Island |
| Paralomis bouvieri Hansen, 1908 | | |
| Paralomis ceres Macpherson, 1989 | | |
| Paralomis chilensis Andrade, 1980 | | |
| Paralomis cristata Takeda & Ohta, 1979 | | |
| Paralomis cristulata Macpherson, 1988 | | |
| Paralomis cubensis Chace, 1939 | | |
| Paralomis danida Takeda & Bussarawit, 2007 | | |
| Paralomis dawsoni Macpherson, 2001 | | New Caledonia, northern New Zealand, and the Solomon Islands |
| Paralomis debodeorum Feldmann, 1998 † | | New Zealand (Middle–Late Miocene) |
| Paralomis diomedeae (Faxon, 1893) | | |
| Paralomis dofleini Balss, 1911 | | |
| Paralomis echidna Ahyong, 2010 | | |
| Paralomis elongata Spiridonov, Turkay, Arntz & Thatje, 2006 | | |
| Paralomis erinacea Macpherson, 1988 | | |
| Paralomis formosa Henderson, 1888 | | |
| Paralomis gowlettholmes Ahyong, 2010 | | |
| Paralomis granulosa (Hombron & Jacquinot, 1846) | False king crab, Chilean snow crab | Chile, Argentina, Falkland Islands |
| Paralomis grossmani Macpherson, 1988 | | |
| Paralomis haigae Eldredge, 1976 | | |
| Paralomis hirtella de Saint Laurent & Macpherson, 1997 | | Lau Basin, North Fiji Basin |
| Paralomis histrix (De Haan, 1849) | | Japan (Tokyo Bay to Kyūshū) |
| Paralomis hystrixoides Sakai, 1980 | | |
| Paralomis inca Haig, 1974 | | |
| Paralomis indica Alcock & Anderson, 1899 | | |
| Paralomis investigatoris Alcock & Anderson, 1899 | | |
| Paralomis jamsteci Takeda & Hashimoto, 1990 | | |
| Paralomis japonica Balss, 1911 | | |
| Paralomis kyushupalauensis Takeda, 1985 | | |
| Paralomis longidactylus Birstein & Vinogradov, 1972 | | |
| Paralomis longipes Faxon, 1893 | | |
| Paralomis macphersoni Muñoz & García-Isarch, 2013 | | |
| Paralomis makarovi Hall & Thatje, 2009 | | |
| Paralomis manningi Williams, Smith & Baco, 2000 | Deep-sea spider crab | West Coast of the United States |
| Paralomis medipacifica Takeda, 1974 | | |
| Paralomis mendagnai Macpherson, 2003 | | |
| Paralomis microps Filhol, 1884 | | |
| Paralomis multispina (Benedict, 1895) | | |
| Paralomis nivosa Hall & Thatje, 2009 | | |
| Paralomis ochthodes Macpherson, 1988 | | Indonesia (Gulf of Boni) |
| Paralomis odawarai (Sakai, 1980) | | |
| Paralomis okitoriensis Takeda, 2019 | | Okinotorishima |
| Paralomis otsuae Wilson, 1990 | | |
| Paralomis pacifica Sakai, 1978 | | |
| Paralomis papillata (Benedict, 1895) | | |
| Paralomis papua Ahyong, 2020 | | |
| Paralomis pectinata Macpherson, 1988 | | |
| Paralomis phrixa Macpherson, 1992 | | |
| Paralomis poorei Ahyong, 2010 | | |
| Paralomis roeleveldae Kensley, 1981 | | |
| Paralomis seagranti Eldredge, 1976 | | |
| Paralomis serrata Macpherson, 1988 | | |
| Paralomis sonne Guzmán, 2009 | | |
| Paralomis spectabilis Hansen, 1908 | | Eastern Greenland, Iceland |
| Paralomis spinosissima Birstein & Vinogradov, 1972 | | |
| Paralomis staplesi Ahyong, 2010 | | Tasman Fracture, Tonga–Kermadec Ridge |
| Paralomis stella Macpherson, 1988 | | |
| Paralomis stevensi Ahyong & Dawson, 2006 | | |
| Paralomis taylorae Ahyong, 2010 | | |
| Paralomis truncatispinosa Takeda & Miyake, 1980 | | East China Sea, Taiwan |
| Paralomis tuberipes Macpherson, 1988 | | Chile (Puerto Aguirre [es]) |
| Paralomis verrilli (Benedict, 1895) | | |
| Paralomis webberi Ahyong, 2010 | | New Zealand |
| Paralomis zealandica Dawson & Yaldwyn, 1971 | Prickly king crab | New Zealand |